More black babies in Chicago die of sudden infant death syndrome than any group, according to a recent University of Chicago study, indicating that genetics may be contributing to some of these deaths.

The UIC study, released in last month’s issue of the Journal of Clinical Investigation, attributed 5 percent of SIDS cases afflicting black infants to a mutation in a gene linked to heart rhythm.

Babies with two copies of the mutated gene are 24 times more likely to die of SIDS than a baby with one or no copy of the gene. About 11 percent of black people carry the altered version of the gene. The researchers didn’t study the gene’s prevalence in white people.

The mutation does not cause SIDS, the researchers emphasized. Instead, it makes a baby more susceptible to environmental risk factors that inhibit breathing, according to researchers.

SIDS occurs when a baby stops breathing while asleep and no other cause of death is known. Doctors do not know what causes SIDS but recommend that babies sleep on their backs on firm mattresses in safe cribs to reduce the risk.

Environment has a huge role in causing SIDS, researchers note, while its effects are most evident in black communities.

About 73 percent of all victims of SIDS in Chicago were black babies, according to the most recent Chicago Department of Public Health data from 2002. Austin, along with Englewood, West Englewood and Gresham, all predominantly black communities, have high SIDS rates. A total of 30 babies died of SIDS in Chicago that year. In suburban Cook County, 10 babies died.

“It’s just sad. If we were the kind of organization with significant funding, I would love to provide [families] with cribs,” said Nancy Maruyama, a registered nurse and executive director of education and community for advocacy group SIDS Illinois. Maruyama had a child die of SIDS in 1985.

A crib, she said, with a fitted mattress and a tightly fitted sheet are all a baby needs to sleep safely.

According to a 2003 study conducted by doctors at Rush University and the University of Chicago, the reduction of SIDS in black babies has occurred slowly compared to other groups. The study’s authors said that SIDS education must target black neighborhoods to see a faster decline in deaths.